Machine-switching telephone system



Feb. 10. 1925. L. POUNKOWSKY 1,525,780

MACHINE SWITCHING TELEPHONE SYSTEM Eil d 5 1919 3 Sheets-Sheet l 1'27van for;

L fpa Pofl'nko wsAy by Fbb.l0.1925.

' L.POUNKOWSKY MACHINE SWITCHING TELEPHONE SYSTEM Filed Nov. 5, 1919 5Sheets-Sheet 2 //7 van/0r Loaa,Fbfivmkomnmfy Any LU o iU o Feb. 10.1925. 1,525,780

1;. POLIN KOWSKY MACHINE SWITCHING TELEPHONE SYSTEM Filed Nov. 5, 1919 3Sheets-Sheet 5 I |.Z.3.4. 7.8.IO. Fl? 3. 3.14.15.

.07 Vania/2' L 11w Po/i r/ro W514 y Patented Feb. 10, 1925.

LIIEKA 1 OIi1ENKG)'WtiKY, 013 ANTHVEIR'JP, RBELGIUIVQLASSIGNORTO'WWESTERN IEI'IECTBIC GOMPANY'JINCORPDRMSLTED,L'OFdNEW YORK, N. "Y;,AGDRPORATION'IOF NEW.YORK.

MACHINE SXVITGHING .TELEEI-IOINE SYSTEM.

Application filed November To all whom it may concern:

- Be it known that L'LIPA POLINKOWSKY, a

citizen of Russia, residingtat. Antwerp'gBelgiuui,have invented certainnew and useful Iu'iproveu'ients in MachhieSwitching =Tcle- Qhone'Systems, of Whichthe following a full, clear, concise andexactdescription. Thisinvention relates to telephone systems and more'particularlycto systems in which automatic 1 switching apparatus isemployed for establishing talking connections.between.subscribers lines.

provision of improved means, in a system where a series ofiautomaticswitches are selectively. controlled. by means of a switch controllingmechanism, is]; immediately associating such mechanism with acallingline when a call is initiated upon said line.

A feature of theinvention consists ,in the provision of. means, in asystem comprising a line; selector and a series of group iselectorswitches forextending calling lines together with ,a switch controllingmechanism adapt, ed to be set by the callingsubscriber tOrCOIk trol"said "selector switches, whereby said controlling mechanism is.imniediately associated with the calling line o ntheiinitiation. ofacall, andmaybe set bythe calling subscriber while said line selector isoperated I to select the calling line. According to. this feature thecalling subscriber, by means .of hisse'nder, may partly set up thecontrolling mechanism during the time the line selector is findinghisline. whereafter the continued operationof said sender serves to sendimpulses over the circuits of the line selector to complete/thesettingof the controlling mechanism.

A. further *featureconsists in. the provision of means, in a system ofthis character involving a switch controlling mechanism' consistingofaplurality of registers forregistering line numbers, 'whereby the.designa tion'of a calling line is automatically registered on saidregisterswhich thereupon operateto directiyely control the line selector to the calling. lineduriug the time the calling subscriber isproceeding to register the, called line designation on said registercontrolling mechanism.

Astill further feature is the provision of means whereby a portion ofthe registers of the controlling mechanism may be set by the callin isubscriber durin the.time the is I n 3, 1919. scrialil'oi $35,464.

remainder of said registers are being automatically positioned inaccordance witlrthe designation of the callinglineto control theoperation ofthe line selector switch, said .lattei' egistei's being alsoavailable to the calling subscriber for registering the remaindcr of thecalled line designation as soonas theyhave completed their function 'ofcontrolling said line selector.

Such other features as arecontemplated. by thepresent invention willbecome more apparent from the'following description and i The object ofthe invention consists 111 thethe appended claims.

In the drawings, 1 shows two subscrihersiines of a groupof calling linestogether with the circuits of a common connecting apparatus forassociating suclrliues with an idle register controlling mechanism.liig. 2 shows deta led circuits of alineselector switch for connectionwith the calling Fig. 2. This figure alsoflillustrates a cord finderswitch for associating a selected controlling mechanism with awlineselector and a first group selector having access to the particulargroupoflines'which contains the calling lines.

In the system embodying the features of this invention there is shown aregister cont'rolling. mechanism 31 0i controlling the selectiveoperation of a series ofautomatic sclector switches .for extendingconnections from tca'lling name a. called line. Since this system asdisclosed is of thefull automatic type, the usualpreliminary or lineselector switch is utilizedlto first extend the calling line. to groupselector switches. 'The" usual practice has been to associate theregistercontroiling mechanism with the circuits of the first groupselector switch whereby such mechanisn'i is not placed under thecontrol. of the calling subscribers line until after the line selectorhas found the callingline. In order that the calling subscriber may nothave to wait until the line selector has found his line, before he canproceed to transmit impulses to the controlling mechanism, the presentinvention contemplates an arrangeu icnt in which such controllingmechanism is immediately associated with the calling line so that thecalling subscriber may proceed to set up the registers thereof prior tothe time that the line selector has moved to the terminals of his line.To accomplish this end the subscribers lines are divided into groups of200 lines, each group appearing as calling lines in the multipleterminals of 200 point line selector switches. Each group of 200 linesis divided into two sub-groups of lines each, namely, an even-hundredsgroup and the next succeeding odd-hundreds group. A further sub-divisionis made by arranging the lines in sub-groups of 20, each sub-groupcomprising ten lines of the first or even-lnindreds and thecorresponding ten lines of the second or odd-hundreds. For example, thefirst of these subgroups of 20 lines would constitute the first tenlines, 0 to 9 of the first oreven-hundreds and in the correspondingfirst ten lines, 100 to 109 of the second or odd-hundreds group.Likewise, the second sub-group of 20 lines would consist of lines 10 to19 of the Zero hundred and lines 110 to 119 of the first hundred etc.

For each subgroup of 20 lines there is provided a common connectingmeans including a group of ten relays which correspond to the unitsdigits of each line in such sub-group. These relays are identified bythe numerals 236 to 239 in Fig. 1, it being considered necessary to showonly a portion thereof. In the disclosure there is shown two lines 099and 199 belonging to the same sub-group of 20 lines. As is obvious, thissub-group comprises lines 090 to 099 and 190 to 199. Common to the unitsrelays 236 to 239 is a sequence switch 210 which, as will be hereinafterdescribed, operates under the control of said units relays to positionthe units register 1 10 of the controlling mechanism shown in Fig. 3,which in turn controls the units selective movement of the line selectorswitch shown in Fig. 2. The tens register which controls the groupselective movement of the line selector switch is automatically set to aposition corresponding to the designation of the group of 20 lines inwhich the calling line appears. By this grouping arrangement the firstgroup of 20 lines appears as calling lines in the first level ofterminals in the line selector switch shown in Fig. 2. The second groupof 20 lines appears in the second level, the third group in the thirdlevel and so on. Vhen, for example, a line, such as lines 099 and 199 ofthe tenth group of 20, initiates a call the particular relay of thegroup of relays 236 to 239, corresponding to the units digit of suchcalling line, is energized and determines that the units register 1 10is automatically set up to a position corresponding to said units digitunder the control of sequence switch 210. Fur

thermore, the fact that the calling line belongs to the tenth groupdetermines that the tens register 130 will be automaticall adjusted toits ninth position as will hereinafter he explained. The tens and unitsregisters 130 and having thus been positioned are then effective tocontrol the line selector switch shown in Fig. 2, first to pick out thelevel of 20 terminals containing the calling line and then to direct itsbrushes on to the terminals of such line.

Vhile the line selector is being operated in this manner to find thecalling line, the call ing subscriber may be operating his impulsesender to position the first two registers, such as the thousandsregister 110 and the hundreds register 120, in accordance with the firsttwo digits of the called line. As soon as the line selector has beendriven to the terminals of the calling line, the mechanism shown in Fig.1 for temporarily associating the calling line with the registercontrolling mechanism, is disconnected and the calling subscriber bycontinuing the opera-- tion of his impulse sender, sets up the tens andunits registers and 1 10 over an impulse circuit which leads through theterminals and brushes of the line selector switch.

The register controlling mechanism shown in Fig. 3 consists of aplurality of sequence switch registers, each having ten circuitcontrolling positions, one for each digit. These registers are drivenunder the control of the subscribers sender to a position correspondingto the number of impulses contained in the series. After having beenpositioned they are driven through their remaining positions, back toposition 0 to control the selective operation of the respectiveswitches. Hence it is obvious that the number of positions through whichthe registers are driven on passing to position 0 is the complement ofthe number of impulses transmitted from the subscribers sender. In orderthat the switches may be controlled in accordance with the digits ofcall numbers as listed in the directory, it is necessary to arrange thesubscribers dials to transmit. the complements rather than the actualdigits themselves. Moreover, the subscribers dials are arranged totransmit a comparatively long impulse at the end of each series. For amore detailed description of the purpose of designing the subscribersdials in this manner reference is made to Patent No. 146,517 ofPolinkowsky-Matthies, filed in Great Britain, October 5, 1921.

The switches and other apparatus employed in this system may be of thesame general construction and operation as shown and described in thepatent to F. R. Mc- Berty, No. 1,097,868, issued May 26, 191i, and thepatent to F. R. McBerty ct al, No. 1,137,223, issued April 27, 1915.

ren'iovin-gliis receiver from the "switclrhook a circuit is establishedfrom ground over the contact and innerarmature of cut-oft relay 207,thence over the loop of tliesubstation and returningbyway-0 f the outerarmature and Contact of relay 207, inner up-per armature and backContact of the units relay 239. inner upper armature and backcon-tact ofrelay 2 19 through "the Windingof line relay 201 to battery and ground.

The relay 249 shown Within thebroken line in the 'upper left-hand cornerofFig. 1 1 corresponds to relay 239. This relay to gether with otherrelays whichcorrespond totherelays 236 to 239, eonstitutea-second commonmechanism for associating calling lines of this particular group of20lines with an idle register inee'hanisn'i. If

the calling inechanisnrshown in 'detail in "Fig. 1 is busy and asecondcall isinitiatecl in this particular group OfllIlGSgtllHSBCOIlCl connnonmechanism illustrated dia ram lnatically Within the broken lines istaken for use to associate such calling :line with a second registermechanism, as shown ln Fig. 3.

cuit is closed fronrbattery, outer righthand armature and back contact0f :relay 211, through the wintling of relay 212', contact and righthand armature of the line relay 20 1, I through the upper Winding of.the units relay239 to ground. Relays 212. and239 areenergized. Relay 239opensrthe circuit of the line relay 2031 and also ithe circuit oftheline re'layi202 individual .tolthe second line etthe pair 099. Relay239 at l the'sametime closes a C11C1119'f10111 glJOllIlCl over itsl0vversar1nature, contact andlower Winding, lettdiand armature and backconi 1 tact of relay 214 through the \vlnchng of .re-

lay 215, contact andvinner Jarniature of ie lay 211 to battery andground. The. relay 215 energizes and promdes1nid1v1dual*test circuitsfor the different register sets such as the one shownin (16139.11 1n:Elgi 1 As sul'ning the register set shown'in Fig. 3 is idle, a circuitis closed from ground over the inner armature and contact-of relay 215through the left-hand Winding of relay 216, contact 322 of sequenceswitch 320, back contact and right hand armature of Erelay 5323, contact327otsequence sWitcl1;32O,'contact352 of sequence switch "350 to batteryand ground. Belay 216 attracts its armatures and provides a holdingcircuit for itself as fOllO-WSE ground, lower armature, contact andlower Winding of relay 239,

lett hand earnratinre and back contact of relay-211 through theleft-hand Winding otrelay 21.1, inner right-hand armature and front"contact of relay 21.6, flll Ollghthe right- }hand Winding of21'6,through the Winding of relay 3223, contact 327 :and JCOIItELCt tobattery-and ground. -Relay 211 opens "the circuit of relay 2-1 5,Whiolrthereupon de energizes While relay 323 opens the test YCIDCIUHT-above traced so that this register set cannot be taken by anothercalling line.

YVhen relay 323 energizes it closes a circuit from ground; through thewinding of relay 324, front contact and fight-hand armature sition 1into Position l Itinay'be well to note at this point that the "OIrOUItSof the register controlling 1116011? anisin shown in Fig. 3 arecontrolledby "meansofflthe two sequence switches 320 and 350. Allsequence switch contacts above the horizontal broken line and to theleft of the vertical broken line are controlled by sequence switch 329*and all-contacts above th'ehorizonta-l broken lineand to thei'ight ofthe vertical broken line are oo-ntrolled bythe sequenceswitch 350. Thesequence switch-contacts Within the srnall'bro'ken line "rectanglesatthe bottom oi Fi 3 'are con- When the llne relay 20l operatesgla c1r-=i a trolled respectively by A the registers 110, 120, 130 and 140. 7'

'lVhen relay 21-1 energizes it also opens the c rouitof relay 212'Whiohin turn deenergizes. If another call in this sub-group is initiatedani'nits*relay'such as relay-249 of the second connecting apparatuslnaynow be energized-overthe armature and back contact of relay 212,thearmature and con- "tact of the line relay201 otthewalling line antlthecontactcofqrelay241 which correspondsto relay 211 oftheapparatus shown.in detail: In the manner described, relav the oalling lineis connectedto an idleeontrolhngfmechanism.

hen relay 324 attracts its armature it closes an energizing circult :torstepping re- ,lay 325"fron1ground and batterythrough the Winding-of saidrelay, contact and miter armature of relay 324, front contact and oftheline to the inner armature and contact ofir'elay 207' andground. At thetime :sequence switclr320 moves into position 2,

relay 331 is energized in acircuit from ground tobattery, contact 326(2) through the Winding of relay 331 to ground at the back contact .andarmature of relay Stepping relay 325 therefore closes a circuit fromground over its armature and front contact, armature and contact ofrelay 331 through the left-hand winding of relay 329, armature andcontact of said relay, contact 311 (2), through the winding of thethousands register to battery and ground. A parallel circuit is alsoclosed for the righthand winding of relay 329 from ground and battery atthe relay to the armature and ground of relay 325. The relay 329 isdifferential and therefore does not attract its armature when bothwindings are energized. The thousands register 110, however, moves outof position 0 and on closing its local contact 111 short-circuits theleft-hand winding of relay 329 which in turn attracts its armature. Theregister 110 under the control of its local contact moves intoposition 1. hen the calling subscriber manipulates his dial inaccordance with the first series of impulses, the first interruption ofthe line circuit causes the deenergization of the stepping relay 325which in turn opens the circuit of the right-hand winding of relay 329.Relay 329, therefore deenergizes. Upon the next closure of the linecircuit, relay 325 attracts its armature and the above traced circuitfor the thousands register 110 is again closed and this register movesout of position 1 and into position 2. For each succeeding interruptionof the line circuit during the transmission of the first series ofimpulses the register 110 advances one position and finally comes torest in a position corresponding to the complement of the number of thethousands digits transmitted. The lastimpulse of the'series beingcomparatively long, the armature of relay 325 remains retracted for alonger period than on the preceding impulses. Relay 334, which isslow-to-attract its armature, is therefore energized over the followingcircuit; battery, at sequence switch contact 342 (2) through the windingof relay 334 to ground at the armature of relay 325. Relay 334attracting its armature closes a circuit for driving sequence switch 320out of position 2 and into position 5.

)Vhen the line circuit is again closed and relay is energized, a circuitis established from ground over the armature and front contact of relay325, armature and contact of relay 321, left-hand winding, armature andcontact of relay 329, sequence switch contact 312 (5), through thewinding of the hundreds register 120, to battery and ground. In themanner already described, the hundreds register is driven from oneposition to another in response to the second series of impulsestransmitted from the calling subscribers dial and comes to rest in aposition corresponding to the complement of the hundreds digit. On thelast interruption of the line at the end of the second series ofimpulses, relay 334 energizes and closes a circuit to drive sequenceswitch 320 out of position 5 and into position 8. It will be noted thatrelay 334 has its circuit opened at the armature of relay 325 to permitof its deenergization prior to the time that se quence switch 320.canreach position 2 or 5 during'the change-over operation.

During the time that the calling subscriber has been setting up thethousands and hundreds registers 110 and 120, the

tens and units registers and have been functioning to directly controlthe operation of the line selector in Fig. 2 to seize the calling line.At the time sequence switch 320 moves in position 2, a circuit is closedas follows to drive sequence switch 350 out of position 1 and intoposition 2: from ground and battery, through the winding of sequenceswitch 350, contact 384 (1) and contact 337 (2) to ground. In position 2of sequence switch 350, a cord finder switch whose brushes are shown at313, 314, 315 and 316, individual to the register mechanism, is drivenby means of power magnet 371 to select a line selector switch havingaccess to the group of lines containing the calling line. The circuitfor power magnet 371 is traceable from ground and battery through thewinding of said magnet, back contact and armature of relay 362 to groundat contact 369 (2). When the test brush 316 reaches a test terminal 370corresponding to an idle line selector having access to; the propergroup, a selectable potential is found on such terminal and thefollowing circu'it established: on Fig. 2, from ground and battery,resistance 272, contact 271 (1) of sequence switch 250, conductor 230,terminal 370 on Fig. 3, brush 316, left-hand high resistance winding oftest relay 364 to ground at contact 369 (2). Test relay 364 energizesand closes a circuit over its low resistance rght-hand windin armatureand contact, through the winding of the second test relay 362 to groundat contact 369 (2) in parallel with the circuit traced through theleft-hand high resistance winding of relay 364. This circuit reduces thepotential on the multiples of terminal 370 so that no other finderswitch will be able to seize such terminals. Relay 362 by energizingopens the circuit of power magnet 371, bringing the brush carriage ofthe finder switch to rest. Relay 362 also closes the following circuitto drive sequence switch 350 over position 3 and into position 4:ground, contact 369 (2 to 3), armature and front contact of relay 362,through the winding of sequence switch magnet 350, to battery andground. 7

During the time the finder switch shown in Fig. 3 is being operated toassociate the register controlling mechanism with an idle line selector,the units and tens registers 140 and 130 are being automaticallypositioned meme in accordancewith-itheunits and, tens digits of thecagllinguline. Eon the purpose ot adjusting: the units register 14,0. toa position corresponding to the units digit of the calling line, theseqnenceuswitc 11 210 is adapted to rum through a number of posi tionscorresponding to theunits digit of. the

calling line. The sequence switch 2l-0 ispro l Videdi with; 20positions, the first ten positions=servi11g to control the setting ofregister 14-0 when the calling line belongs tot-the second ten lines: ofthe sub-group of 20- as, for eX-a1nple, thelineyl99sini question. Thesecond ten, positions: of sequence switch 210, namelypositions 10 to1,9, serve tocontrol the setting of the units register l tO when thecalling line belongs; to theifirst ten: lines of the group of 20; as,for example, the line 099 A relay 2118is provided, for the purpose ofstarting sequenceswitch; 210

tronrits position 0. The circuit for, enengizing relay 213 leads] from:guounded, battery to the outer armature andifront C011."

tactof relayEZll, where itisclosed, and further through the right-handwinding of relay 213,0onta1ct 290, (0) to groundt at, the lower armatureand back contact of relay 239 assuming that the unitsrelay 239iisnotenergized. When: I sequence, switch 21-0. reachesposition-i L thecircuitof relay-21.33

is maintained over contact 290 (1),, back" sequence switch 210isdriven-fi'0m position to position until a units relay is. found withits armatures attracted. In the case as sumed, however, where line "199is the call-- mg line whose units digit is the tenth or 210 remained in;its normal position 0. As.- soon as the relay 3% attracts its armaturewhen the i register controlling mechanism" is seized the stepping; relay3551s energized as follows: from grounded battery, ove-rqcontact2201otsequence switch 210,; leflirhfiil'ld" armature and contaetof relay216,}; resistance 5335, contact andnnner. armatul: V g an, contactbtifiv (1) ofsequence sw1tcl1- 35Q,

tact and middle arnrature of relay 324,, armature and front contact ofrelay 3515, contact 000 (1) through-the winding of re; lay374 to batterycand, groundL- Relayfifl kis energized and provides a locking circuitforitselfover its; left-hand armature and; contact l tdof units/register:140. The regise ters 149 and 130 normally stand in position 1, beingmoyed into this position as willfbe hereinafter described at, the timethe, register, controlling. mechanism is, restored: to normal, The relay374, which is for translating purposes, being ener gizedfat this time,later determines that the line" selector in 2 will, be driven over thefirst or evenhundreds section of its, terminal bank and into thesecondor odd; hundreds section where the terminals of the line 199.. appear. F

As soon as sequence switc'lt 350 moves into position. 2, as, hasalreadybeen described, the following circuit is completed for the tensregister 1305 fnom, rounded battery, throughfthe winding of saidregister, con.- tact. 134 1 contact-"3,61 (2),. had: contact. andarmature of relay 366, front contact and armatureofrelay 355 a ground at'con tact 338; (2,); The register 130 which, at

this time,, is standing in position 1 startsfto rotate, Since thecalling line belongs to the tenth, or No. 9 group offZOlines', relay 216individual to this group is energized andbatterypotential from groundand: battery of oontact 220, is placed upon; Contact 136 in position 9over left-hand armature and contact of relay 21,6 and the conduct-or333. The tens register 130, therefore, continues to rotate until itreachesposition 9, atwhich time a circuit is closed from grounded,battery, contact 2200f sequence switclr 210, left-hand armature andcontact of relay 216, conductor383, c0ntact l36 (9) throughthe windingof'relay 366 to, ground; Relay 366'opens at its armature and backcontact the above traced circuit for the tens register 130.

Register 180consequently stops in position 9. Relay 366 at its armaturea'nd front contact closes-a circuit as follows from grounded batteryover the slow operating relay 368 front-contact andarmature of relay366, front contact. and armature ct relay 355, to ground at contact 338vof sequence switch 320. If

sequence switch: 350 has already reached position 4., after the'finderswitch has found; an :idle line selector or as soon as such sequenceswitch does reach; position at, the following circi'lit is; established:ground conr tact 37'z t l) o tsequence switch 350,, armature. andcontact of relay 368 through the winding: of sequence switch 350 tobattery and"; ground. Sequence. switch 356) thereupon "fmoa es intoposition 5.

through the'winding otrelay" 3575 to glioi lnctat contact (1). Relay 355'is energized. and establishes-a circuit from ground, con,

pose; a fundamentalcircuit including stepping relay 355 and controlrelay 252 is established as follows: from grounded battery, to thewinding of relay 252, contact 253 (l) of sequence switch 250, conductor234, brush 3144, contact and armature of relay 357, contact 356 (5) ofsequence switch 350, through the winding of stepping relay 355 to groundat contact 358 Relay 252 is energized and closes a circuit from groundand battery, through the winding of sequence switch 250, contact 254 (1)of this sequence switch to front contact, armature and ground at relay252. Sequence switch 250 moves out of position 1 and into position 2. Inleaving position 1, sequence switch 250 opens contact 271, the circuitleading over conductor 230, terminal 370, brush 316 and the left-handwinding of test relay 364 to ground at contact 369. In passing throughposition 1% this sequence switch closes a circuit for the right-handwinding of relay 273, including contact 256 (l of sequence switch 250.Relay 273 is energized and at its left-hand armature and contact closesa circuit for its left-hand high resistance winding over conductor 230,and terminal 370, in series with the left-hand winding of relay 364 tocontact 369 and ground. The relay 364 is unable to maintain itsenergization in series with the left-hand winding of relay 273 andtherefore releases its armature. In position 2 of sequence switch 250,the tripping spindle power magnet 258 is energized over a circuitincluding contact 257 (2) and the front contact and armature of relay252. The brush tripping spindle is thereby rotated and for each brushtripping position passed over, a short circuit is placed around thestepping relay 355 by means of the interrupter contact 255. Upon thefirst deenergization of the stepping relay 355, a circuit is completedfrom ground, contact 338, of sequence switch 320 armature and backcontact of relay 355, left-hand winding and armature and contact ofdifferential relay 359, contact 361 (5), contact 134, through thewinding of the tens register 130, to battery and ground. The tensregister 130 moves out of the position in which it is standing and bymeans of its local contact 131, short-circuits the lefthand winding ofdifferential relay 359 permitting this relay to energize. hen the shortcircuit is removed at the interrupter contact 255 and relay 355 isenergized, the relay 359 releases its armatures in the manner alreadydescribed in connection with the operation of relay 329. This operationcontinues until the tens register 130 reaches position 0, at which timea circuit is closed from grounded battery, through the winding ofsequence switch 350, contact 373 (5), contact 134 (0), contact 361 (5),contact and armature and left-hand winding of re lay 359, back contactand armature of relay 355 to ground at the sequence switch contact 338.The sequence switch 350, therefore, moves out of position 5 and intoposition 7.

In parallel with the circuit above traced for sequence switch 350, acircuit is closed for relay 357. Relay 357 serves to open thefundamental circuit to prevent any further operation of the switchduring the change-over period. As soon, after the fundamental circuit isopened at the register mechanism, as the interrupter contact 255 isopened, the control relay 252 deenergizes and in so doing closes acircuit from grourd over its armature and back contact, contact 254 (2),through the winding of sequence switch 250 to battery and ground wherebysequence switch 250 advances into position 3.

With the sequence switch 350 in position 7 the fundamental circuit isagain closed by contact 356 (7) at the controlling mecha nism and relays355 and 252 become again energized. Belay 252 at its front contactcloses a circuit including contact 254 (3) for driving sequence switch250 out of position 3 and into position 4. In position 4 of sequenceswitch 250, the brush carriage power magnet 261 of the line selector isenergized in a circuit including contact 262 (4) and the back contactand armature of relay 252. The brush carriage is rotated moving theselected set of brushes 231, 232 and 233 over the level of 20 terminalscontaining the terminals 242, 243 and 244 of the calling line. For eachset of terminals passed over the interrupter contact 267 connects thewinding of relay 252 directly to ground in shunt of stepping relay 355.At the first closure of the contact 267, relay 355 releases its armatureand closes a circuit from ground, contact 338 of sequence 320, armatureand back contact of relay left-hand winding and armature and contact ofrelay 359, contact 367 (7) of sequence switch 350, contact 142 of theunits register 140, through the winding of said register and battery toground. The register 140 which, it will be remembered, is standing inposition 1, the units digits of the calling line being 9, is energizedin this circuit and moves into position 2. IVhcn its local contact 143closes between positions 1 and 2, the left-hand winding of differentialrelay 359 is shunted out and this relay is energized by means of itsright-hand winding. As interrupter contact 267 opens, the stepping relayis energized opening the circuit of the right-hand winding of relay 359causing said relay to release its armature. As the line selector brushesapproach the next set of terminals the interrupter contact 267 closes,relay 355 is deenergized and the above traced circuit is closed for theunits register 140. The register 140 thereupon moves out of position 2and into loo Menergized, advances from position it rose to the groupcontaining thecalliiigflina minals for each position"throu gliywhich theunits register" 140 passes. Upon the next deenergization of relay355;at'tert'he units register 140 reaches position 0, the io'lloxvingcircuit is closed for driving register M0- into position 15 groundcont-act armature and-hac kc'ontact of relay 855,1et't-hand Wirtding,armature and contact of rela 359, contact 36? (7 5 contact 142 (0) ri'gharmature and frontxcontact of rela through the \vindin g' or registcrleO to hat-1 tery and grmmd; Having passed positionO, the registerlaOcontinues to'rotate throughairadditionalcycle coming to rest again inposition 0' and, as a result, causes the line selector *hrushes to beadvanced ten additional steps to-the terminals- 242; 2t3 and 24st of thecalling line 199, which appear in the second or' Odd-InnidredS sectionof the terminal hank. Wnenregister 140 passed from position 0tozposition' 1, ground was removed from." contact= 146 {and relay 3745deit ci'icrgized; Therefore as register 140 reachesu position 0 at theend of its second rotation; a circuit is closed from grounded batterythrough the "winding of sequence switch 350,

contact 330; back contact l and rig lit-hand armature ofre lay 37 4:;"contact 142 (0); contact 367 (7 cont-act andar'mature and left? handWinding of relay 359, baclc contact and armature of relay to contact andground. In parallel Wit-hthis circuit, a cir-' cu'italso closed for thecnergization o'f relay 357 which seryesto open the funda mental circuit;Sequence switch350 being i 7 into position 8. When the interruptercontact 267 opens after theope i'iing ofthe tundamental circuit at thearlnatiire and contact of relay 357, the control relay 252 isdeenergized and completes a circuit 1 including contact 254: fordrivingsequenceswitch 250 into position Thus, in response tothe=initiation of the i call on line 199, 'au idle register controllingmechanism has been associated therewith, by means of the commonconnecting ap paratus shown in Fig; 1, i the selectedvidle. controllinglnecl'lanisni automatically assoa ciated with a line selector switchha'Y'ng ac-w thertens anduni-ts digits of theq calling line automatirallyifegistered: on-said controlling mechanism anduthe line. selec'torsWitch dircctively operated, in accordance \ith such registration toextendflthe calling line throughto the circuits of a fi rst group lectorwhose hruslres are shownat 223,224 and "225. During this operation whichtakes place in a veryshort period ottime, thecalli-ng subscriber may heroceeding as from ground and batter y hereinbefore described to setupthe thousands and lnindredsregisters of the controlling mechanism inaccordance with the first two' digits of tliecalled line 200. Consider,for enample, that the calling subscriber has just c'oi'nl et'ed thesending of the first two series ot' impulses over the impulse circuitprepared by the common connecting apparatus shown in Fig. l to thestepping relay825 when: the line-selector switch has completed itsoperation and sequence switches 250 and 350 have moved respectively intopositions 5 and 8. That is to say, the;

thousands andwlmndreds registers and "have-heenj positioned by impulsessent from the calling sub-station over the impulse circuit which wasimmediately prepared by the connnon connectlng apparatus at tl ieinitiati on oil the calla The calling line having' been found by theline selector,"

however, this common connecting apparatus 1s no longer l-equired and maynow be rea leased to tlreuse oithe othersubscribers? lines in thegroupto Wl'IlCihlt is individual. Release of the common connecting. means 1nFig. 1 takes: place at the tnnesequencc switch 350 leaves position 7. tOn leavingposition 7, contact 352 opens the closing cirting these relaysto deenergize. Inthe case assumed the sequence switch 210 is stand in'gwlOGL Inorderthat the remaining registers 130 r and 140 of thecontrolling mechanism may he set up in accordance with the oalledlinenumber, a second impulsecircuit front the calling substation tothesteppln g relay of theline selector switch. This circuit may betraced from ground and battery through the Winding of stepping relay325, contact 363 (8),"brush 313, conductor 218, contact the; commonapparatus, Figb 1, when-sequence -switch 250' moved into position 5. TheCH'CHlt for cut-oli relay 207 IS traceable Winding of sai-d relay,contact 2M, liruslr 233- to ground at contact 266 (5).

The calling suhsci'iher,- continuing 'to opcrate his sender sends aseries of. impulses over the second impulse circuit correspond contactrelay 331, lefti ha-nd Winding, arinas.

at and through the 120 i 105: is prepared over the terminals and brushesture and contact of relay 329, contact 311 of sequence switch 320,which, it will be remembered, is standing in position 8, through thewinding of register 130 to battery and ground. The register 130 havingbeen brought to position 0, as was explained, in controlling theoperation of the line selector switch, is advanced into position 1 atits local contact. This register closes a shunt at its local contactaround the left hand winding of relay 329 permitting said relay to beenergized. hen the linecircuit is opened on the first impulse in thetens series, relay 325 is. deenergized, causing in turn thedeenergization of differential relay 329. At the next closure of the.line circuit the register 130 advances from position 1 to position 2 andso on for each succeeding impulse, coming finally to rest in a positioncorresponding to the tens digit of the desired line. On the lastcomparatively long interruption of the line circuit at the end of thetens series, relay 325 releases its armature for an interval sufiicientto allow the energization of the slow operating relay 33 i. Relay 334;closes a circuit to drive sequence switch 320 out of position 8. Relay334 is soon deenergized, due to the closure of the line circuit, so thatsequence switch 320 comes to rest when it reaches position 11.

In position 11 of sequence switch 320, the following circuit is closed:from ground, to armature and front contact of relay 325, armature andcontact of relay 331, left-hand winding, armature and contact of relay329, contact 312 (11) to the winding of the units register 1&0 tobattery and ground. The units register 140 which, like the tensregister, was left in position 0 at the end of line selection, isenergized and moves into position 1. On passing to position 1 thisregister at its local contact shunts out the lefthand winding of relay329 permitting said relay to attract its armature by means of a circuitclosed through its right-hand winding. hen the calling line is openedfor the first impulse in the units series, stepping relay releases itsarmature and opens the circuit of the right-hand winding of relay Relay329 thereupon is deenergized. \Vhen the line circuit is again closed andrelay 325 attracts its armature, the units register 140 is againenergized and advances into position 2. This procedure continues, theunits register moving from position to position until the last impulsein the series has been sent. The last interruption being comparativelylong, relay 334 is energized as explained and sequence switch 320advances from position 11 into position 14.

The brush tripping operation of the first group selector takes placesimmediately upon the controlling mechanism having been associatedtherewith, provided the calling subscriber has, at this time, completedthe registration of the thousands digit on the register 110. Theregister 110 having been positioned, it will be recalled that sequenceswitch 320 thereupon moves from position 2 into position 5. If, at thistime, the sequence switch 350 has reached position 8, the followingcircuit is closed to drive said sequence switch into position 10: fromground to battery through the winding of sequence switch 350, contact384 (8) and contact 337 (5) to ground. In position 10 of sequence switch350 the usual fundamental circuit for controlling the brush trippingoperation of the first group selector is again completed as follows:from grounded battery, through the winding of relay 252, contact 253,conductor 234, brush 314, contact and armature of relay 357, contact 356(10), through the winding of stepping relay 355 to ground at contact358. Relays and 252 are energized in this circuit. At the armature andfront contact of relay a circuit is closed including contact 254 (5) fordriving sequence switch 250 into position 6. In position 6 of sequenceswitch 250 the brush tripping spindle power magnet 278 of the firstgroup selector is energized over the following circuit: from groundedbattery, through the winding of power magnet 278, contact 276 (6) tofront contact and armature of relay 252 and ground. The brush trippingspindle rotates and for each tripping position the winding of relay 252is connected direct to ground by means of a circuit including contact259 (6) and the interrupter contact 27 This direct circuit to groundshunts out the stepping relay in the fundamental circuit causing saidrelay to be deenergized. Upon the first deenergization of relay 355 acircuit is closed from ground, contact 338, armature and. back contactof relay 355, left-hand winding and armature and contact of relay 359,contact 367 (10), right-hand armature and back contact of relay 376,contact 114%, through the winding of the thousands register 110 tobattery and ground. The thousands register moves from the position towhich it was adjusted by the called subscribeifs sender to the nextsucceeding position. At its local contact 111 the register 110 shuntsout the left-hand winding of relay 2559 permitting this relay toenergize. When the interrupter contact 275 is opened, relay 355 is againenergized causing in turn the dcenergization of the differential relay359.

On each succeeding deenergization of the relay 355 the thousandsregister is advanced from position to position until it reaches position0. On the following deenergization of relay 355, after the thousandsregister has reached position 0, a circuit is closed from groundedbattery through the winding of sequence switch 350, contact 373 (10),

switch 320 moves into position 1&1, these uence switch350 is advancedfrom position o'into position 17. Thjecincuit fordrii ing sequenceswitch 350 into positionf17includes "cahta taso and banner 3 10. Inposition 17 biitter yliiid ground. The register ldd advances from one'position to the next and upon reaching position o," the iiQllOWlIiLgciremit isf'clcssdz farms grounded *-battery, thitough the winding ofsequenceswitch 350,

I contact 330 (17 back contact and righthand rniature of relay374,contact 1 12 ha nd; winding of reliayisss, back contact andarmatureotfreleyfifi, to Contact 338 and gr-ennui sequencefsi'vitch 3 50moves "from bosltioii 17 into position 1.-

lVhen sequence swltch 3:30reaches position 1acircuitis'closed fordriving sequence switch320 back to it's normal position. This circuitincludes contact 832](14: to 15) and conflict 3 19 "When sequenceswitch-320 passes through positioirlfi closes a circuit attenuates 336for the tens register 1 30.

This i-iagister, therefore; moves from position 0 into position 1 W'heie it is found when-the register-controlling mechanism taken for useby" acalling line. Likewise the units i gisterltd is 'driyen from ED ition 0into position 1 'bymea'ns of a circuit momentarily abstain contact 336as seguence switch 320 passes through positionl'i. The registercontrolling "inechanism is now completely restored o itsnorin'alcondition ready for i use in connection with subsequentcalls:

As sequence switch 850 leaves position 1 7 it opens at contact 369theabove-traced circuit of relay 273- Relay 273 being deenergized, closes acircuit froni grounded battery, through the winding of sequence switch250, Contact 260 (9) back contact'and armature of supervisory relay 271, to the righth'andar natur e and contact of relay 273 and groundSequence switch 250, therefore fias sesover position 11 and comes torest in position 12. When the called subscriber answers, the supervisoryrelay 274: is enerfiized inserieswith the called line andthe right-handwindingsot' therepe ating coil 269. At ltS' 1-1;T1l&t\ll6 andfrontcontact relay 274closesa circuit including contact 254 (12) todrive sequence si iiteh 2:30 intoposi- -tion" 13,-whichis thetalkingposition thereot." The calling, line is thus extended oversequence switch contacts 263 and 264 through to the left-hand windingsof the repez tting coil 2 69 and conversation may take place. In postion 13 of sequence switch 230 a circuit is closed from grounded batteryto resistancejQfiQ, contact 271 (13) to the winding of relay and ground.The relay 277 which is slow to attract its arma- 1111168 'ei ierg'izesafterthe lapse of a definite interval.

i ttthe end of the conversation when the eqeiyers are replaced to theswitchhook, relay Q68 and 274% are ldeenergil ed and relay 268' closesacii'cuit for il'elay 252 including Contact 2 33 (13).. Relay 252 inturn con1- a circuit over itsnrmature and front switch 21 Land le ftfhand armature of relay 277, conv r t tact 2:66 to 16) brush238, terminal244-, ContactBG-T (17) i contact{armature "and leftth ng-11 the -windingof message register =3Q5 through the negative pole of s ing line.

Infposition 17 of sequence switch 350 the slow-operating relay 277which, up to this tiniefis locked up over a circuit including itsContact and right-hand armature, is hort-circuited by the ground atcontact Relay QZT ftheretore, is deenergized. The brush carriage of theline selector is ew. restored to normal by means or a circuit fromgrounded battery through the winding of power magnet 261, Contact 262-(l'fifback Contact and armature of relay to ground. 11s 1 the brushcarriage reaches its, home position, relay 252 is en er ized in acircuit including contact 259 andhrus h @206. Relay 252 closes acircuitincluding contact 254: (17) for driv seqi i ence switch 250 intoposition 18. In position 18, the brush carriage oiirthe firstfgroupselector is returned to its normal position by means of a circuit fromgroundedebatterythrough the Winding of brush carriagepower magnet 281,back. contact and armature of relay 282, to contact 283 and ground. Thenthe first group selector lirusl carriage has been connaletcly restored,acircuitis established from grounded battery tl'ni'ough the winding ofmagnet 109, centact 286 (18), brush 20S and its home contact, throughthe winding of relay 282, tocontact 283 (18) i and ground, Relay 282attractsits armatiire and'closes a circuit including contact for drivingsequence switch 250 back to its normal position 1. Release of thesucceeding selectors 235 and 251 takes place in the well-known manner.

Had the called line 200 been busy at the time the final selectorcompletedits units contact .112 (0), back contact and righthand armatureof relay 376, contact 367 (10), contact and armature and left-handwinding of relay 359, back contact and armature of relay 355, to contact338 and ground. In parallel with this circuit a circuit is alsocompleted for relay 357. Relay 357 opens the fundamental circuit whilesequence switch 350 energizes and moves from position 10 into position11. The brush tripping spindle has now been rotated to a position fortripping the proper set of brushes and the fundamental circuit is openedat the register controlling mecha nism as register reaches position 0.The next opening of the interrupter contact 275 permits the controlrelay 252 to be de energized. Relay 252 closes a circuit over itsarmature and back contact and contact 254 for driving sequence switch250 out of position 6 and into position 7.

The selected set of brushes 223, 224 and 225 are next driven over thelevel of trunk terminals leading to second group selectors such as theselector shown at 235. For this purpose the brush carriage power magnet281 is energized in a circuit from grounded battery through the windingof said magnet, back contact and armature of relay 282, to ground atcontact 283 When the test brush 225 of the first selector engages aterminal 226 having a selectable potential thereon, the test relay 284is energized in a circuit through its left-hand winding to ground atcontact 283. Relay 284 attracts its armature and closes a low resistancepath through its right-hand winding and the winding of relay 282 toground at contact 283. This low resistance circuit decreases thepotential on terminal 226 sufiiciently to render the same non-selectableto other first group selectors. The relay 282 which is energized at thesame time, opens the cir cuit of the power magnet 281, bringing thebrush carriage to rest. A circuit is also completed for sequence switch250 from grounded battery through the winding of sequence switch 250,front contact and armature of relay 282 to ground at contact 283.Sequence switch 250 advances from position '7 over position 8 and intoposition 9.

If at this time the calling subscriber has completed the setting of thesecond or hundreds register 120, sequence switch 320 will have beendriven into position 8. Hence a circuit is established from groundedbattery through the winding of sequence switch 350, contact 365 (11),contact 339 (8) to ground. Sequence switch 350 thereupon moves fromposition 11 into position 13. The fundamental circuit is again closedfrom the register controlling mechanism through to the second groupselector 235. This circuit leads from the second group selector overbrush 223, contact 289 (9), conductor 240, brush 315, contact 358 (13),through the winding of stepping magnet 355, contact 356 (13), armatureand contact of relay 357, brush 314, conductor 234, cont-act 288 (9),and thence over brush 224 to the second group selector. In thewell-known manner the brush tripping operation at this selector switchtakes place under the control of the hundreds register 120. For eachshunting of the stepping relay 355, during the rotation of the brushtripping spindle, the register is advanced from one position to anotherby means of the following circuit: ground, contact 338, armature andback contact of relay 355, left-hand winding, armature and contact ofrelay 359, contact 381 (13), contact 124, through the winding ofregister 120 to battery and ground. On reaching position 0, the register120 closes a circuit traceable from grounded battery, through theWinding of sequence switch 350, contact 373 (13), contact 112 (0),contact 124 (0), contact 381 (13), contact and armature and left-handwinding of relay 359, back contact and armature of relay 355, to contact338 and ground. Sequence switch 350 thereby moves into position 14.Trunk hunting now takes place at the second group selector and a trunkis selected leading to an idle final selector switch such as the oneshown at 251.

Provided the calling subscriber has completed the setting of the tensregister 130, at this time, sequence switch 320 will have been movedinto position 11. Consequently sequence switch 350 is driven out ofposition 14 and into position 15 by means ot a circuit including contact365 (14) and contact 339. In position 15 of sequence switch 350 thefundamental circuit is closed at contact 356 and extends through to thefinal selector switch 251. Brush selection takes place at the finalselector, under the control of the tens register 130, the stepping relay355 being deenergized for each brush-tripping position passed over bythe tripping spindle. At each deenergization of relay the tens registeris advanced from one position to another by means of the followingcircuit: ground, contact 338, armature and back contact of relaylett-hand winding, armature and contact of relay 359, contact 361contact 134, through the winding of tens register 130, to battery andground. When register reaches position 0 the sequence switch 350 ismoved into position 16 by means of a circuit from grounded batterythrough the winding of sequence switch 350, contact 373 (15), contact134 (0), contact 361 (5), contact, armature and left-hand winding ofrelay 359. back contact and armature of relay to contact 338 and ground.

Assuming that the units register has already been positioned, whensequence lit) . select selection, the relay 27 1 would not have operatedin; series with said line. Therefore, sequence switch 250 remains inposition 12 and the slow-operating relay 277 is not energized. When thecalling subscriber replaces the receiver to the switchhook and relay 252is energized as explained, sequence switch 250. advances from position12 directly into position 17. In passing through position 13, thecircuit of relay 277 is not closed for a suflicient length of time topermit this relay to attract its armatures. Therefore, in passingthrough positions 14 to 16, the sequence switch contact 266 is withouteffect to apply meteringcurrent to the thirdconductor of the callingline and message register 205 is not operated to charge the call.

It will now be assumed that the subscribers line 099 belonging to theeven-hundred group, and which corresponds to the line 199 in the samesub-group of 20 lines, initiates a call. In this case the line relay 202is energized instead of relay 201. Relay 202 closes a circuit fromgrounded battery, outer armature and back contact of relay 211, windingof relay 212, through the right-hand winding of relay 214-, contact andright-hand armature of relay 202 to upper winding of relay 239 andground. Relay 239 is energized and closes a circuit over its lowerarmature and contact through its lower winding, left-hand armature,front contact and left-hand winding of relay 214., through the windingof relay 215, to inner armature and contact of relay 211 to battery andground. Relay 215 closes a circuit as hereinbefore described, to an idlecontrolling mechanism. When relay 216 is energized to associate thecalling line with the controlling mechanism the left-hand winding ofrelay 214; is included in the circuit with the right-hand winding ofrelay 216. Relay 211 also energizes at this time and since relay 214 isenergized, the following circuit is established for relay 213: fromgrounded battery, to outer armature and front contact of relay 211,lefthand winding of relay 213, contact 222 (0), to outer right-handarmature and contact of relay 214 and ground. Relay 213 at its armatureand contact closes a circuit for sequence switch 210 which. passes fromposition 0 to position 10,v disregarding which of theunits relays 236 to239 is energized. On reaching position 10, the circuit of the left-handwinding of relay 213 is opened at contact 222 and since relay 239 is theone which is energized, no circuit exists over the contact 290 for theright-hand winding of relay 213, therefore, this relay releases itsarmature and causes sequence switch 210 to stop in osition 10.

As herein efore explained the relay 37 1 was energized and lockedup whensequence switch 320 moved into position 2 by means of a circuit closedat the armature and front contact of relay 355. When sequence switch 210passes from position 0 to position 1, it.

opens at contact 220 the above-traced circuit for relay 355. This relayat its armature and back contact closes a circuit from grounded batterythrough the winding 01 the units register 140, contact 142, contact.

to position 1, register 140 opens the locking 4C at contact 1 16,permitcircuit of relay 31 ting this relay to release its armatures. Therelay 374 being deenergized, the register 140 stops in position 0instead O'l' running through an additional cycle when it later becomeseffective to control units selective operation of the line selectorswitch. By this expedient the brushes 231, 232 and 233 of the lineselector are caused to stop on the terminals of the calling line 099which appear in the first of the even hundreds section of the terminalbank. From this point on the operation is the same as that described indetail in connection with the initiatiou of a call on line 199.

Assuming next that the calling lines instead of being the tenth ortwentieth line in the sub-group of 20, as in the cases discussed, hadbeen either the eighth or eighteenth lines, for example, the unitsdigits oi these'lines would, therefore be 7, and relay 237 is the relaythat would be taken for use when either of such lines initiates a call.VVhenrelay 211 is energized, a circuit is first closed as follows forthe right-hand winding of relay 213: from grounded battery, to outerarmature and front contact of relay 211, through the right-hand windingof relay 213, contact 290 (0), to back contact and lower armature ofrelay 239 and ground. Relay 213 is energized and closes This operationcontinues, the register 140 be; p

The opening of cont-act 220 21s,,

a circuit to drive sequence switch 210 out 7 of position 0 and intoposition 1. In position 1 sequence switch 210 continues to ro tate sincerelay 213 maintains its energiza tion in a circuit over contact. 290 (1)and the back contacts and lower armatures of relays 238 and 239. When,however, se-

(ill

for its righthand winding over sequence switch contact 291 During thetime that sequence switch 210 is passing from po sition O to position 2its contact 220 interrupts the circuit of relay which in turn causes theunits register 140 to be advanced as already described to a positioncorresponding to the units digit of the calling line.

hen the common connecting means shown in Fig. 1 is released, after thecalling subscribers line has been selected under the control of the tensand units registers 130 and 140, relay 211 does not deenergize as wasthe case when sequence switch 210 remained in position 0. Instead relay211 maintains its armature attracted by means of an energizing circuitfrom ground an d battery, through its right-hand winding to contact 221and ground, closed in some position from 1 to 19. Hence when relay 237releases its armaturcs. a circuit established from ground and battery toouter armature and front contact of relay 211, through the right-handwinding of relay 213. contact 291 (2), back contacts and arinaturesofrelays 237, 238 and 239 to ground. Relay 213 at tracts its armatureand closes a circuit to drive sequence switch 210 out of position 2 andinto. position 0. Relay 213 maintains its energization during therotation of sequeuce switch 210 over a circuit including contacts 290,291, 292 and 293 and back contacts and arinatures of relays 236, 237.238 and 289. On passing out of position 19 sequence switch contact 221opens the circuit of relay 211, permitting this relay to be deenergizedwhich in turn causes the deenergization of relay 213. Sequence switch210, therefore, comes to rest in position 0 and the common connectingapparatus is ready to be taken for another call.

In order that the register-controlling n'icchanism, which is positionedby impulses transmitted in accordance with the decimal system ofnumbers, may be adapted to deliver impulses for controlling theoperation of the selector switches, in accordance with the system onwhich switches of this character are operated, relays 374 and 3.76 areprovided for accomplishing the necessary translation. Should thethousands digit of the called line he odd, the contact 115 is connectedto ground as soon as the thousands register 110 has been positioned fromthe calling subscribers sender. When se quence switch 350 passes fromposition 8 to position 10 it closes in position 9 the following circuit:from grounded battery, through the winding of relay 376, contact 378(9), contact 115, to ground. Relay 376 attracts its armatures andprovides a lock-.- ing circuit for itself over its left-hand armatureand contact and contact 377. \Vith relay 376 energized and sequenceswitch 850 in position 10, the thousands register 110 is operated overthe following circuit to control the brush tripping operation of thefirst group selector: from ground and battery, at and through thewinding of register 110, contact 11%, front contact and right-handarmature of relay 3.76, contact 367 (10), and thence to ground as abovedescribed, at. sequence switch contact 338. Since the contact 114 isclosed only in positions 1 to S, inclusive, theregister 110 comes torest in position 9. rather than in position 0. The result is that thesame level of terminals is selected at the first group selector for thisparticular mid-thousands digit as would have been chosen had thethousands digitbeen the next lower even digit. Sequence switch 350 nowadvances into position 13 where brush selection takes place at thesecond group selector, under the control of the hundreds register 120.Register 120 is advanced from its set position to position 0 in themanner already described. In position 0 of register 120 the thousandsregister 110 is now moved from position 9 into position 0 by means ofthe following circuit: from grounded battery, through the winding ofregister 110, contact 112, contact 12 1 (0), contact 381 (13), andthence to sequence switch contact and ground. This additional step ofthe thousands register 110 results in the rotation through an additionalposition of the second group selector brush tripping spindle. Therefore,.a level of trunks is selected leading to final selectors having accessto the proper odd-thousands group. \Vith the register 110 in position 0,sequence switch 350 is driven from position 13 into position 1 1 bymeans of the circuit hereinlmfore traced.

Should the hundreds digit of the called line he odd, contact 126 of thehundreds register is connected to ground and relay 371 is energized overa circuit including contact as sequence switch 350 passes throughposition 12. Relay 37 1 looks up in a circuit from grounded batterythrough its winding, left-hand contact and armature and contact 1&6 toground. \Vhen the units register 140 reaches position 0 during the unitsselection at the final selector 251, the sequence switch not driven outof position 17 as before, since the relay $371 is now energized.Register 1 10 is, therefore, energized over the following circuit andleaving position 0 makes a complete additional cycle of operation: fromgrounded battery, through the winding of said, register, front contactand right-hand armature of relay 37%, contact 142 (0). contact 367(17)., and thence to sequence switch contact 338 and ground. Thisadditional cycle of the units register causes the selected set ofbrushes at the final selector to be advanced l till over the firstsection of the terminal bank and onto the terminals of the called linein the second or odd-hundredssection of said bank. Asregister 140 passesfrom position 0 to position 1 contact 146 is opened and relay 374deenergized, Hence when register 14:0 again comes intoposition 0 itceases to rotate.

What is claimed is:

1. Ina telephone system, a calling line, a line selector andgroup-selectors for extending said line, a register controllingmechanlsm tor controlling the operation of said selectors, meansresponsive to the initiation of a call on said line for associating saidmechanism therewith, means for operating the line selector to select thecalling line, an

impulse circuit established upon the association of said mechanism withsaid line, a second impulse circuit established When the line selectorhas selected the calling line,

means controlled by the calling subscriber IiiOl' sending impulses overboth of said cir' cuits, and means responsive to such impulses forsetting said controlllng mechanism.

2. In a telephone system, a calllng llne, a

line selector and group selectors for extend ing said line, a registercontrolling mech anism for controllmg the operation of sa1d selectors,means responsive to the mitiation H of a call on said line forassociating said mechanism therewith, means for operating the lineselector to select the calling line, an impulse circuit established uponthe associa tion. of said mechanism With said line, a second impulsecircuit established over the line selector as soon as said line selectorhas selected the calling line, means controlled by the callingsubscriber for sending im pulses over both of said circuits, and means Iresponsive to such impulses for setting said controlling mechanlsm.

In a telephone system, a calling line, a line selector and groupselectors for extend ing said line, a register controlling mechanisurfor controlling the operation of said selectors, means responsive to theinitiation of a call on said line for associating said mechanism therewth, means for operat ng the line selector to select the calling line, an

impulse circuit established uponthe association of said mechanism withsaid line, a sec- Cir 4.111 a telephone system, a calling line, a

line selector and group selectorsfor extending said line, a registercontrolling mechanlsm for controlling theoperation of said selectors,means responsive to the initiation of the call on said lineiorassociating said mechanism therewith, means for operating the lineselector to select the calling line, an impulse circuit established uponthe associa tion of said mechanism with said line, a second impulsecircuit established when the line selector has selectedthe calling line,means controlled by the calling subscriber for sending impulses oversaid first circuit while the line selector is selecting the calling lineand for sending impulses over said second circuit after said line isselected, and means responsive to the impulses sent over said firstcircuit for setting a portion of said controlling mechanism, said lastmeans being responsive to the impulses sent over said second circuit forcompleting the setting of said mechanism. 7

5. In a telephone system, a calling line, a line selector and groupselectors for extend ing said line, controlling mechanism comprising aplurality; of registers for controlling the operation of said selectors,means responsive to the initiation of the call on said line forassociating said mechanism therewith, means for operating the lineselector to select the calling line, an impulse circuit established uponthe associationofsaid mechanism with said line, a second impulse circuitestablished When the line selector has selected the calling line,-meanscontrolled by the calling subscriber for sending impulses over saidfirst circuit while the line selector is selecting the calling line andfor sending impulses over said second circuit after said line isselected, and means responsive to the impulses sent over said firstcircuit for setting certain of said registers, said last named meansbeing responsive to the impulses sent over said second circuit forsetting the remainderot said registers.

6. In a telephone system, a group of lines, a line selector and groupselectors for extending said lines, a register controlling mechanism forcontrolling the operation of said selectors, connecting means common tothe lines of said group, said connecting means being responsive to theinitiation of a call on one of said lines for connecting saidcontrolling mechanism to such line, means for operating said lineselector to select the calling line, an impulse circuit established bysaid connecting means, a second; impulse circuit established by the lineselector after the calling line is selected, means for sending impulsesover saldfirst circuit While said line selector is operating and forsending impulses over said second circuit after the line selector hascompleted its operation, and means responsive to such impulses forsetting said controlling mechanism. a

7 In a telephone system, a groupof lines, divided into sub-groups, aline selector and groupselectors for extending said lines, a registercontrollingmechanism for control.- ling the operation of said selectors,a plu ialityof connecting means each individual to one ot-saidsub-groups, each connecting means being responsive to the initiation ofa call on a line in the corresponding subgroup for connecting saidmechanism to such line, means for operating-said line selector-to,select the calling line, an impulse circuit established by saidconnecting means while said line selector is in operation, a secondimpulse circuit established by the line selector at the completion ofits op eration, means for sending impulses first over one and then overthe other of said circuits,and means responsive to such impulses forsetting said controlling mechanism.

8. In a telephonesystem, ttglOllP of lines,

a line selector and group selectors for tending said lines, a registercontrolling mechanism for controlling the operation oi? said selectors,connecting means com mon to the lines of said group, said con nectingmeans being responsive to the initiation of a call on one of said linesfor connecting said mechanism to such line, means tor operating the lineselector to select the calling line, anv impulse circuit establishcchbysaid: connecting means during, the operation of the line selector, means'tor'relcasing said connecting means as soon as the line selector hascompleted. its operation, a second impulse circuit established by theline selector at the completion of its: operation, means "for sendingimpulses over both: of; said circuits, and means rcsponsive to suchimpulses for settingsaid controlling;mechanism.

9; Ina telephonesystem, a group oflines, a, line selector andgroupselectors for extending,- said; lines-controlling mechanism comprising aplurality of registers for controlling the operation of said selectors,connectingmeanscommon totlie lines of said group, said connectingmeansbeing responsiveto the initiation of a callon one ofsa ddines forconnecting said mechanism tousuch, lines, means for operating the linemeans for -releasing said connecting means assoon. as the line selector,has completedv its operation, a second impulse circuit establishe'd bythe line selector at; the completion ofits" operation, means controlledby the calling subscriber for send ingimpulses first over one i. andthenover the other ct said circuits, and, means responsive to; the inipulsessent over said first circuit for setting certainof said registers,saiddast-n-amed means being responsive to the 1 impulses sent over saidsecond circuit for setting the re mainder of said registers.

'10. 111 a telephone system, acalling line, a line selector-and groupselectors for ex tending said line, a register controlling mechanism forcontrolling the operation of said selectors, means responsive to theinitiation of a call on said line for associating said mechanismtherewith, means for associating said mechanism with said line selector,means for operating said line selector to select the calling line, animpulse circuit for sending iinpuses over the callin line to saidmechanism while the line se'cctor is selecting said line, a secondimpulse circuit established upon theselection of the calling line forsending impulses over said line to saidunechanis n, and means responsiveto such impulses tor setting said mechanism;

11. In a telephone system, a calling line, a line selector and groupselectors for eX- t-ending said line, a register controlling mechanismfor controlling the operation of said selectors, means responsive to theinitiation of a call on said line for associating said mechanismtherewith, a finder switch for associating said mechanismwith said lineselector. means for oieratin said line selector to select the callingline, an impulse circuit for sending impulses over the calling line tosaid mechanism while the line sclector is selecting said line, a secondimpulse circuit established upon the selection of the calling line forsending impulses over said line to said mechanism, and means responsivcto such impulses for setting said mechanism.

12. In a telephone system, a calling line. a pluralityv of lineselectors and group selectors for extending said line, a registercontrolling.- mechanism for controlling the operation of said selectors,means responsive to the initiation of a call on said line forassociating said mechanism therewith, a finderswitchlfor associatingsaid mechanism with an idle one oi": said line selectors, means for.operating said line selector to select the callingline, an impulsecircuit forsending impulses over the calling line to said mechanismwhile the line selector is selecting said line, a second impulse circuitestablished upon the selection of the calling line for sending impulsesover said line to said mechanism, and'means responsive to such impulsesfor setting said mechanism.

13. In a telephone system, a calling line, a line selector and groupselectors for extending said line,- controlling mechanism, meansresponsive to the initiation of acall on said line for associating saidmechanism"therewith, means for registering the designation of said lineon said mechani-sm, means controlled. byf'said mechanism l l t inaccordance with the designation registered for operating said lineselector to select the calling line, means for setting a portion of saidmechanism in accordance with a desired designation during the operationof the line selector, means established by the line selector at the endof its operation for completing the setting of said mechanism inaccordance with the desired designation, and means controlled by saidmechanism in accordance with the desired designation for operating saidgroup selectors.

141. In a telephone system, a calling line, a line selector and groupselectors "for eX- tending said line, controlling mechanism, meansresponsive to the initiation of a call on said line for associating saidmechanism therewith, means operated automatically upon the associationof said mechanism with the calling line for registering the designationof said line onsaid mechanism, means controlled by said mechanism inaccordance with the designation registered for operating said lineselector to select the calling line, means for setting a portion of saidmechanism in accordance with a desired designation during the operationof the line selector, means established by the line selector at the endof its operation for completing the setting of said mechanism inaccordance with the desired designation, and means controlled by saidmechanism in accordance with the desired designation for operating saidgroup selectors.

In a telephone system, a calling line, a plurality of line selectors andgroup selectors tor extending said line, controlling nieclnu'iism, meansresponsive to the initiat ion 0! a call onsaid line for associating saidmechanism therewith, means for associating said mechanism with an idleone of said selectors, means for registering the designation of saidline on said mechanism, means controlled by said mechanism in accordancewith the designation registered for operating said line selector toselect the calling line, means for setting a portion of said mechanismin accordance with a desired designation during the operation of theline selector, means established by the line selector at the end of itsoperation for completing the setting of said mechanism in accordancewith the desired designation, and means controlled by said mechanism inaccordance with the desired designation for operating said groupselectors.

16. In a telephone system, a calling line, a plurality of line selectorsand group selectors for extending said line, controlling mechanism,means responsive to the initiation of a call on said line forassociating said mechanism therewith, a finder switch individual to saidmechanism for associating the same with an idle one of said lineselectors, means for registering the desig nation. of said line on saidmechanism, means controlled by said mechanism in accordance with thedesignation registered for operating said line selector to select thecalling line, means for setting a portion of said mechanism inaccordance with a desired designation during the operation of the lineselector, means established by the line selector at the end of itsoperation for completing the setting of said mechanism in accordancewith the desired designation, and means controlled by said mechanism inaccordance with the desired designation for operating said groupselectors.

17. In a telephone system, a calling line, line selectors and groupselectors for extending said line, controlling mechanism comprising aplurality of registers, means responsive to the initiation of a call onsaid line for associating said mechanism therewith, means forpositioninga portion of said registers according to the designation of said line,means controlled by said positioned registers for operating the lineselector to select the calling line, means for positioning the remainderof said registers in accordance with a desired designation, means forrepositioning said first positioned registers in accordance with thedesired des ignation, and means controlled by said reg isters foroperating said group selectors in accordance with said desireddesignation.

18. In a telephone system, a calling line, line selectors and groupselectors for extending said line, controlling mechanism comprising aplurality of registers, means responsive to the initiation of a call onsaid line for associating said mechanism therewith, means forpositioning a portion of said registers according to the designation ofsaid line, means controlled by said positioned registers for operatingthe line selector to select the calling line, means for positioning theremainder of said registers in accordance with a desired designationduring the operation of the line selector, means eli ective after thecalling line is selected for repositioning said first positionedregisters in accordance with the desired designation, and meanscontrolled by said registers for operating said group selectors inaccordance with said desired designation.

In witness whereof, I hereunto subscribe my name this 11th day ofOctober A. D., 1919.

LIPA POLINKOWVSKY.

